Rub the salt all over the pork. Using a paring knife, stab the pork in several places and fill each pocket with a piece of garlic, pancetta and carrots.
Place the pork into a bowl or container large enough to fit it snugly along with the onions. Tuck the rosemary and bay in, then pour over the vinegar. The pork and onions should be completely submerged. If not, try using a smaller container or simply pour over more vinegar.
Cover and refrigerate overnight.
Remove the pork from the fridge and drain very well, discarding the vinegar. Keep the onions, rosemary and bay leaves and set aside.
Heat a large heavy-based pot over medium-high flame. Pour in the oil then sear the pork on all sides until golden. Remove the pork from the pot and set aside.
Toss the reserved onions into the hot oil and sauté for several minutes until a bit golden on the edges. Add the garlic and prunes and cook for a further 1 minute.
Place the pork back into the pot and nestle it in with the onions and prunes, pour over the prošek, red wine and add the reserved rosemary and bay leaves. Add the Vegeta and black pepper.
Bring to the boil, then reduce to a simmer. Place the lid on and cook for 2 hours, turning the pork over once during cooking.
Turn the heat off and carefully remove the pork from the liquid. Set it on chopping board and cut into thick chunks.
Remove and discard the rosemary and bay leaves from the cooking liquid. Using a stick blender, blitz the cooking liquid, onions and prunes to a puree. Check for seasoning. Place the cut pork back into the liquid and cook a little more, if needed.